Semyon Tsvigun was born into a large family of Ukrainian peasants,[1] in Stratievka village, in the Chechelnyk District of Odesa Governorate, located near the Vinnytsia region of Ukraine.

This was at a time when Joseph Stalin and the new chief of police, Lavrentiy Beria were preparing to seize the former Russian-ruled province of Bessarabia from Romania, to create the Moldavian Soviet Socialist Republic, now (Moldova).

Through this connection, he became an important member of the so-called Dnipropetrovsk Mafia, who were the core of Brezhnev's political support during his time as General Secretary of the Communist Party of the Soviet Union.

These books are usually bought by the state at a great discount, but Tsvigun's wife had no intention of paying for them, and pretended that her husband needed them for professional reasons.

"[4][8] Medvedev believed that she was Brezhnev's wife's sister, but there is no mention of this alleged kinship in the extensive archives posted online by the Tsviguns' granddaughter Violetta Nichkova.

Unusually for someone so senior, his obituary was only signed by five top officials (Andropov, Gorbachev, Chernenko, Ustinov and Aliyev) rather than the entire Politburo and Secretariat.

Andropov then quit the chairmanship of the KGB to take over Suslov's former position in the party secretariat, putting him clearly in line to succeed Brezhnev, who died ten months later.

After Suslov's death, a story circulated that the latter had had a heart attack brought on by a confrontation with General Tsvigun over a corruption scandal involving diamond smuggling, in which Brezhnev's daughter Galina, her husband, General Yuri Churbanov, a deputy minister for internal affairs, the head of the Moscow circus, Anatoli Kolevatov, and a former circus artist named Boris 'the Gypsy' Buryata, were implicated.

Suslov reputedly summoned Tsvigun, accused him of protecting the criminals because of his link to the Brezhnev family, and warned him that he was likely to be expelled from the party and put on trial.

[10] This version was contradicted by a subsequent chairman of the KGB, Vladimir Kryuchkov, who said that Tsvigun committed suicide because he was ill from cancer, and had had a lung removed.